Tubular incandescent lamp

ABSTRACT

A tubular incandescent lamp adapted to be mounted for operation in positions other than horizontal comprising a transparent envelope receiving thereinside a single-spiral incandescent body rigidly connected with a pair of electric leads sealingly secured in said envelope, and at least one holder supporting the incandescent body inside said envelope; the lamp being additionally provided with at least one auxiliary support means including a tube welded to the inner surface said envelope, and with the tube receiving therein a portion of an adjacent one of a holder supporting the incandescent body.

United States Patent Prytkov 51 July 4, 1972 [54] TUBULAR INCANDESCENTLAMP [72] Inventor: Evgeny Fedorovich Prytkov, Bolshevistskaya ulitsa,30, kv. 3, Saransk Mordovskoi, U.S.SR,

[22] Filed: Sept. 30, 1970 [21] Appl.No.: 76,773

827,274 11/1969 Canada ..313/279 946,149 1/1964 Great Britain 1,527,8826/1968 France Great Britain ..313/279 Primary Examiner-David SchonbergAssistant Examiner-Paul A. Sacher Attorney-Waters, Roditi, Schwartz &Nissen [5 7] ABSTRACT A tubular incandescent lamp adapted to be mountedfor operation in positions other than horizontal comprising atransparent envelope receiving thereinside a single-spiral incandescentbody rigidly connected with a pair of electric leads sealingly securedin said envelope, and at least one holder supporting the incandescentbody inside said envelope; the lamp being additionally provided with atleast one auxiliary support means including a tube welded to the innersurface said envelope, and with the tube receiving therein a portion ofan adjacent one of a holder supporting the incandescent body.

2 Claims, 1 Drawing Figure TUBULAR INCANDESCENT LAMP The presentinvention relates to tubular incandescent lamps adapted to be mountedfor operation in positions other than horizontal, including a positionwhen the single-spiral incandescent body of the lamp extends vertically,the lamp being also adapted to withstand vibratory and shock loads.

Commonly known are vibration-proof incandescent tubular lamps, eachcomprising a transparent envelope having therein a single-spiralincandescent body rigidly connected to a pair of leads sealingly securedin the envelope, and a plurality of discshaped holders supporting theincandescent body in the envelope. In order to prevent displacement ofthese holders under the action of vibratory loads, the internal surfaceof the envelope is made so as to include a longitudinally extending rib,this rib being produced during the process of the manufacture of thetubular envelope, and with the disc holders being provided withindentations complementary to the cross-sec-' tional shape of the rib.

Also commonly known is another type of tubular incandescent lampcomprising a transparent envelope having therein a single-spiralincandescent body rigidly connected with a pair of electric leads whichare sealingly secured in the envelope, and a plurality of disc-shapedholders supporting the incandescent body within the envelope. In orderto prevent deformation of the incandescent body under the influence ofexternal mechanical loads, the holders are built into the sidewall ofthe envelope from two diametrically opposed sides, whereby indentedareas are formed in the respective portions of the external surface ofthe envelope.

It is a disadvantage of both to afore described prior art structuresthat the lamps essentially cannot be mounted for operation in positionsother than substantially horizontal, lest the incandescent body besubjected to deformation resulting in the eventual destruction of theenvelope, under the influence of the weight of the incandescent body andof external mechanical loads.

Among other disadvantages of the known structures for tubularincandescent lamps are that the hard-melting or refractory materialsfrom which the holders for the incandescent body are usually made, arepoorly fastened to glass. In order to solder or weld the holders intothe envelope, the quarz of the envelope must be heated to a very hightemperature, and the holders themselves are required to be very thin,whereby more often than not the sidewall of the envelope is piercedduring the holder-securing operation, whereby the percentage ofacceptable lamps is greatly reduced in the production thereof. Moreover,the wall strength of the envelope of such a lamp is reduced because ofthe wall having thin areas at the points where the holders are secured,whereby the lamp becomes more vulnerable to breaking during operation.Additionally the diametrically opposed indentations in the externalsurface of the lamp, resulting from securing the holders thereinside,are liable to adversely affect the uniformity of the light flux producedby the lamp, which reduces the utility of such lamps for illuminationpurposes in various optical and illumination systems.

It is an object of the present invention to eliminate theabove-mentioned disadvantages.

The main object of the present invention is to provide a tubularincandescent lamp with a single-spiral incandescence body, which iscapable of withstanding relatively great external mechanical loads andwhich should be adapted to be mounted for operation in positions otherthan substantially horizontal, in view of the modified structure andsecuring of the holders supporting the incandescent body in the envelopeof the lamp.

This object is accomplished by providing a tubular incandescent lampcomprising a transparent envelope having therein a single-spiralincandescent body which is rigidly connected with at least a pair ofleads sealingly secured in the envelope, and plurality of wire holdersfor supporting the incandescent body within the envelope, and wherein,in accordance at least one additional support means including a tubewelded to the inner wall surface of the envelope, the tube havingfastened thereto a portion of an adjacent one of the plurality ofholders supporting the incandescent body.

It is expedient for the tube to be introduced into the envelope throughthe exhaust portion thereof and to weld the tube thereto, wherebyenabling the tube to support and retain the holder for supporting theincandescent body.

The herein disclosed structure of the lamp provides for an increasedreliability in the performance thereof when it is mounted for operationin a position other than substantially horizontal, including positionswhen the single-spiral incandescent body extends vertically, and alsowhen subjected to the influence of external mechanical loads, with thisincreased reliability being due to the additional linking of theincandescent body with the tubular envelope.

The hereinafter disclosed configuration and structure of the holdersupporting the incandescent body provides for the comparatively easilyperformed connection thereof with the additional support means retainingthe holder with reference to the envelope.

The structure of the herein disclosed lamp makes it possible to employthe lamp in a variety of optical and illumination systems, since thereis practically no distortion of the light flux produced by the lamp,whereby the lamp can be used for a number of important applications,e.g. in the shooting of cinema and TV films.

The present invention may also be embodied in lamps which are to be usedin installations and under conditions, where the presence of vibratoryand external shock loads prohibits the employment of lamps of thepresently known prior art types.

The economy of the incorporation of lamps according to the invention invarious installations and apparatuses is determined by the increaseddependability in the performance of these lamps; since it has been foundthat in various applications one lamp of the herein disclosed structuremay replace more than 10 lamps of the previously know types.

The present invention will be better understood from the followingdetailed description of an embodiment thereof, reference being had tothe accompanying drawing depicting a longitudinal sectional and partlyschematic view of a tubular incandescent lamp constructed in accordancewith the inventron.

Referring now in particular to the drawing, the lamp com prises agenerally tubular glass envelope or bulb 1 having an inner surface la,and opposite end portions 2 through which the respectively two metalfoil leads extend in a sealed relationship.

Extending along the longitudinal axis of the glass envelope 1 is asingle-spiral incandescent body 4 supported centrally thereof by aplurality of wire holders 5, each wire holder 5 being shaped as a ringhaving the external portion thereof extending contiguously with theinternal surface of the envelope 1, and with the diameter of the ringbeing smaller than the intemal diameter la of the envelope 1.

The opposite end portions of the incandescent body 4 are supported inthe respective ones of a pair of lead-in wires 6, each wire 6 includinga pair of eoaxially wound cylindrical members, with each member beingformed by a plurality of coils of tungsten wire, and with the twocylindrical members having different diameters. The smaller diametercylindrical member of the wire 6 has the same winding pitch as theincandescent body 4, and is threaded or screwed onto the respective endportion of the incandescent body, while the larger diameter cylindricalmember of the wire 6 adjoins the internal surface la of the glassenvelope 1. The smaller diameter cylindrical member of the wire 6 isformed integral with a longitudinal extension of which the external orfree end is welded or soldered to a respective metal foil lead 3.

Welded or soldered to the end portion of the metal foil lead 3, oppositeto that to which the extension of the respective smaller diametercylindrical member of the lead-in wire 6 is with the present invention,the lamp envelope is provided with secured, is an electrode 7 which isconnected to a contactmaking socket part 8 of a structure 9 forcontacting the respective ceramic end base of the lamp.

The contact-making socket part 8 has a firm electric contact with theelectrode 7 and is firmly secured in the ceramic end base structure 9,without requiring the use of any basesecuring composition. When the baseof the herein disclosed lamp is assembled, a predetermined quantity ofmetal is applied into the structure 9, e.g. such as copper-phosphorousalloy or silver solder, whereafter this amount is heated up to itsmelting point, and the electrode 7 is immersed into the molten metalsoas to wet the electrode. When the molten metal is then cooled down so asto solidify, it forms the contact-making socket part 8 onto which thestructure 9 of the ceramic end base is secured.

The contact-making socket part 8 is adapted to form an electricalcontact with the supply mains (not shown). Disposed adjacent to theportion 10 of one of the holders and snugly receiving this portiontherein is a tubular piece 11 which is welded integrally with theexhaust spout of the envelope l. The envelope 1 of the herein disclosedlamp which is provided with this branch piece in the form of the tube 11which is welded to the envelope body and receives the portion 10 of theholder 5, so as to hold the latter rigidly and reliably secured withinthe lamp and in a desired position.

The internal diameter of the tube 11 being somewhat greater than thediameter of the wire from which the holder 5 is made, the portion 10 ofthe latter can be introduced into the tube 11 without requiring anyexcessive assembling effort.

The portion 10 of the holder 5 is elbow-shaped, so as to prevent directcontact of the tube 11 with the incandescent body 4, lest the latter maybe glazed and possibly destroyed in the operation of the lampv When thelamp according to the invention is mounted in a vertical position andconnected to the electrical current supply, the tube 11 preventsdeformation of the incandescent body 4, and appreciably reduces bendingand curving of this body under the influence of its own weight andexternal mechanical load, since the holder 5 by having its end portion10 firmly connected with the envelope 1 with the aid of the tube 11 willnot change its initial position.

The reduction of the lengths in the supported spans of the single-spiralincandescent body of the lamp intermediate of the points in which thisbody is firmly supported increases the dependability of the performanceof the lamp under the influence of vibratory and shock loads.

We claim:

1. A tubular incandescent lamp comprising:

a transparent envelope having rigidly attached thereto at least a pairof electric leads sealingly secured in said envelope; a singlespiralincandescent body extending axially and centrally within said envelopeand rigidly connected with said electric leads; at least one additionalsupport means including a radially inwardly extending tube welded to theinner surface of said envelope; a holder encompassing said incandescentbody within said envelope; said holder having a projecting portionfastened within said tube.

2. A tubular incandescent lamp according to claim 1, wherein said tubeis introduced into said envelope through an exhaust portion thereof,said tube being welded to the inner surface of said envelope forsupporting and retaining said holder within said incandescent body.

1. A tubular incandescent lamp comprising: a transparent envelope havingrigidly attached thereto at least a pair of electric leads sealinglysecured in said envelope; a single spiral incandescent body extendingaxially and centrally within said envelope and rigidly connected withsaid electric leads; at least one additional support means including aradially inwardly extending tube welded to the inner surface of saidenvelope; a holder encompassing said incandescent body within saidenvelope; said holder having a projecting portion fastened within saidtube.
 2. A tubular incandescent lamp according to claim 1, wherein saidtube is introduced into said envelope through an exhaust portionthereof, said tube being welded to the inner surface of said envelopefor supporting and retaining said holder within said incandescent body.